In general, mobile communication systems have been developed to provide communication services while guaranteeing user mobility. Thanks to rapid technological advancement, mobile communication systems are capable of providing not only voice communication services but also high-speed data communication services.
With recent introduction of various packet services, small-sized packets are sporadically and frequently generated. In a general mobile communication system like LTE, to transmit even a small packet, it is required to establish a connection and configure a data bearer through control messages.
This may require exchange of many control messages. When many user equipments wishing to transmit and receive a small amount of data perform the connection establishment procedure, serious network load may be caused. Moreover, exchange of many control messages may degrade battery performance in user equipments.
Currently, IP data generated by a user equipment is treated uniformly and transmitted through a wireless network regardless of data characteristics. For example, the user equipment uses the same scheme to transmit a keep alive message with a size of 300 bytes or to transmit video data with a size of 100 Mbytes.
For example, in the case of the LTE network, when IP data is generated in a user equipment in idle mode, the user equipment receives allocation of radio and network resources to transition to connected mode for IP data transmission. That is, the user equipment performs RRC establishment, sends a Service Request message to the network for bearer activation, and performs bearer activation for data transmission. When no data is present for a preset time after data transmission, the user equipment transitions back to idle mode.
As described above, the user equipment has to perform mode transition for data transmission and the network has to allocate radio and network resources correspondingly. However, it will be more efficient to transmit small-sized data, which allows low-rate and delay-tolerant transmission such as a keep alive message with a size of 300 bytes, through a scheme reducing overhead due to control messages in comparison to an existing scheme.
For example, it is possible to transmit small-sized data such as a keep alive message by use of an RRC control message transmitted during RRC establishment or a NAS control message transmitted after RRC establishment. In this case, the network may save resources by skipping bearer setup for data transmission and reduce overhead due to control messages.
As a scheme for identifying data characteristics, the screen state of a user equipment may be used to determine whether data is to be transmitted in the background. That is, only data being sent while the screen is off may be regarded as background data. However, this scheme may fail to consider that file transfer or the like can be performed while the screen is off.
Hence, for efficient data transmission, it is necessary to develop a scheme to accurately identify characteristics of data to be sent by a user equipment.